DHS Bulletin on Denial of Service (TDoS) Attacks on PSAPs

The Department of Homeland Security (DHS) NCCIC - National
Coordinating Center for Communications – the DHS-Office of Emergency
Communications, DHS - Office of Infrastructure Protection, Federal
Communications Commission, the National Cyber and Forensics Training Alliance,
the FBI-National Cyber Investigative Joint Task Force working in coordination
with the National Emergency Number Association (NENA), the Association of
Public Safety Communications Officials (APCO) International, Louisiana Fusion Center,
Mansfield Police Department and telecommunications service providers to
identify and mitigate the effects of a criminal Telephony Denial of Service
(TDoS) against public safety communications, hospitals and ambulance
services. This is for immediate dissemination to public safety answering
points (PSAPs) and emergency communications centers and personnel.

Background: Information received from multiple
jurisdictions indicates the possibility of attacks targeting the telephone
systems of public sector entities. Dozens of such attacks have targeted
the administrative PSAP lines (not the 911 emergency line), The
perpetrators of the attack have launched high volume of calls against the
target network, tying up the system from receiving legitimate calls. This
type of attack is referred to as a TDoS or Telephony Denial of Service
attack. These attacks are ongoing. Many similar attacks have
occurred targeting various businesses and public entities, including the
financial sector and other public emergency operations interests, including air
ambulance, ambulance and hospital communications.

Scheme: These recent TDoS attacks are part of
an extortion scheme. This scheme starts with a phone call to an organization
from an individual claiming to represent a collections company for payday
loans. The caller usually has a strong accent of some sort and asks to
speak with a current or former employee concerning an outstanding debt.
Failing to get payment from an individual or organization, the perpetrator
launches a TDoS attack. The organization will be inundated with a
continuous stream of calls for an unspecified, but lengthy period of
time. The attack can prevent both incoming and/or outgoing calls from
being completed. It is speculated that government offices/emergency services
are being "targeted” because of the necessity of functional phone lines.

What we know:

The
attacks resulted in enough volume to cause a roll over to the alternate
facility.

The
attacks last for intermittent time periods over several hours. They
may stop for several hours, then resume. Once attacked, the attacks
can start randomly over weeks or months.

The
attacks followed a person with a heavy accent demanding payment of $5,000
from the company because of default by an employee who either no longer
works at the PSAP or never did.

What we need from victims:

Additional
insight into the scope and impact of the event- specifically how many
communications centers have been attacked is critical to identifying the
true scope of this occurrence.

In
order to ensure situational awareness with our members and member
agencies, it is critical that this information be disseminated to
emergency communications centers, PSAP’s, government IT departments, and
any related government agency with a vested interest in emergency
communications continuity of operations.